HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Rice, S. K. Articles by Schneider, N. Search for Related Content PubMed Articles by Rice, S. K. Articles by Schneider, N. Agricola Articles by Rice, S. K. Articles by Schneider, N.

Cushion size, surface roughness, and the control of water balance and carbon flux in the cushion moss Leucobryum glaucum (Leucobryaceae)¹

Department of Biological Sciences, Union College, Schenectady, New York 12308 USA

We explored the size dependence of water balance and carbon flux in the cushion moss Leucobryum glaucum (Leucobryaceae). Conductance to water vapor (g_a) was modeled empirically using 4–24 cm diameter cushions (N = 14) evaluated across wind speeds from 0.7 to 4.3 m/s in a wind tunnel. Model parameters included wind speed (u), kinematic viscosity (v), cushion diameter (L_d), and surface roughness (L_r). The model g_a = –9.62(u/v)^1.21 · L_d^–0.35 · L_r-in^–1.85 (where L_r-in represents a dimensionless form of L_r; R² = 0.88) indicates negative relationships between g_a and both L_d and L_r. These predictions were evaluated during a 5-d field experiment where water loss and net carbon exchange (estimated by F/F_m') were monitored. In the field (N = 18, 4–34 cm diameter cushions), L_r, but not L_d, controlled rates of evaporation due to additional turbulence that reduced size dependence of cushions along the forest floor. However, the duration of positive net carbon gain varied from 1.4 to 4.4 d and was significantly longer in larger diameter cushions. Thus, under field conditions, size-dependent changes in surface-area-to-volume relationships influence the duration of net carbon gain more than differences in water flux and lead to a strong size dependence of water balance and carbon flux.

Key Words: allometry • boundary layer • bryophyte • growth form • Leucobryaceae • Leucobryum glaucum • life form • water budget

This article has been cited by other articles:

				J. H. C. Cornelissen, S. I. Lang, N. A. Soudzilovskaia, and H. J. During Comparative Cryptogam Ecology: A Review of Bryophyte and Lichen Traits that Drive Biogeochemistry Ann. Bot., May 1, 2007; 99(5): 987 - 1001. [Abstract] [Full Text] [PDF]